import javax.xml.bind.annotation.XmlInlineBinaryData;
import java.util.Scanner;

/**
 * Created with Intellij IDEA.
 * Description;
 * User:墨琦
 * Data:2023-03-30
 * Time:17:39
 */
public class Text1 {
    public static void main(String[] args) {
        StringBuffer fw=new StringBuffer();
        String ee;
        Scanner sc=new Scanner(System.in);
        String kk=sc.nextLine();
        char[] as=kk.toCharArray();
        for(int i=0;i<as.length;i++)
        {
            ee=fw.toString();
            if(ee.indexOf(as[i])==-1) {
                fw.append(as[i]);
            }
        }
        System.out.println(fw.toString());

    }
}
